Constellation 2652

First-generation Constellation of the bumper-movementBumper automaticAn automatic winding system whose pivoting weight travels through a limited arc, meeting spring buffers at the ends of its swing. Wrist motion moves the weight to wind the mainspring. Unlike a full-rotation rotor, the weight cannot turn continuously through 360 degrees; the travel angle varies by design. era (calibers 351, 352, 354): star and model name above six, observatory medallion on the caseback, arrow (diamond) gold markers on a pie-pan dial.